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The primary treatment of MTC is surgical removal
of all neoplastic tissue present in the neck. Patients
presenting with palpable disease should undergo
a staging work-up and pheochromocytoma must
be carefully excluded. Several studies have suggested
that survival in patients with MTC is
dependent upon the adequacy of the initialsurgical
procedure. This is accomplished by total
thyroidectomy and bilateral lymph-node dissection.
Total thyroidectomy is indicated for both the hereditary and sporadic forms of MTC. In most hereditary cases, C cell hyperplasia is bilateral and may give rise to foci of MTC; 5 % of apparently sporadic MTC’s prove to be index-cases of hereditary forms ; finally, even in sporadic forms, bilateral disease is found in 30 % of cases. Lymph node dissection is indicated during primary surgery because lymph node metastases occur in up to 10 % of cases with primary lesions of less than 1.0 cm in diameter and in up to 90 % of cases with clinical tumors. Bilateral « en bloc » dissection of central neck and of lateral neck com-partments should be performed. In gene carriers detected by prospective family screening who have no overt thyroid lesion, total thyroidectomy and central compartment node dissection may be curative. Whether dissection of the central compartment should be routinely performed in young gene carriers with no evidence of disease, is still controversial. The four parathyroid glands should be identified during surgery. In a patient with evidence of hyperparathyroidism, if a gland appears to be enlarged or if an adenoma is clearly present, it should be removed. If diffuse hyperplasia is found in each of the glands, then removal of all four with autotransplantation of only a portion of one gland to the non dominant forearm is performed. In patients with proven adrenal medullary disease, the abnormal adrenal medullary tissue should be resected prior to thyroidectomy, in order to avoid hypertensive crisis during anesthesia. Our strategy is to remove only the affected adrenal gland(s). Approximately one third of patients who undergo a unilateral adrenalectomy will eventually require reintervention for a contralateral pheochromocytoma but this may not occur for many years during which the patient will not be steroid dependent. Patients with bilateral pheochromocytomas should be treated with bilateral adrenalectomy. |
